"The main argument for this option is that increased capabilities in electronics and information technology have generally reduced the need for humans to fly space missions," the report says on page 74. "The scientific instruments used to gather knowledge in space rely much less (or not at all) on nearby humans to operate them."

The downside to relying on robots and other technology is that it will mean no human flight to Mars, the report says, and if robots later prove inadequate to a critical task, the human spaceflight program would have to be rebooted from scratch.

The report doesn't recommend taking this step, one of many it spells out for reducing the deficit, but simply says this is one option. Other options would make major cuts in Pentagon spending, health spending and funding for the arts, among other things. The report is simply designed to give Congress an idea of what could be saved where, should it choose to do so. There are also options presented for raising revenue to help cut the deficit.